The present invention relates to the treatment of malodours, in particular, airborne malodours which may be caused or carried by airborne particles or by entities in a gaseous state.
A known method of counteracting or neutralising a malodour involves the use of an aerosol spray device containing a composition comprising one or more malodour counteractants and which, when activated, produces an aerosol spray which may be targeted at the source of the malodour. Various known products are marketed for this purpose.
Where the malodour is caused wholly or partly by airborne particles, a low collision rate between the malodour counteractant and the malodour particle occurs using known aerosol spray devices and so results in an inefficient malodour counteracting process. The practical consequence of this inefficiency is that the malodour counteractant, which may be or may include a malodour masking ingredient, has to be used in large amounts in order to achieve the desired effect. This in turn leads to unwanted side effects, such as a strong perfume smell or a limited fragrance choice.
Even when the malodour is caused wholly or partly by a non-particulate airborne source, the use of the known aerosol spray devices containing malodour counteracting compositions is still rather inefficient. In order to deliver an aerosol spray which can be projected over a reasonable distance, the design of the device, and in particular, the design of the spray head of the device, results in the emission of a spray with a small spread angle. Thus, most of the spray travels at least initially along or close to a central spray line extending from the spray head. Accordingly, if the source of the malodour spreads out to a significant extent spatially in directions lateral to the line of spray, it is necessary to deliver a large amount of the aerosol spray in order effectively to dispose of the malodour. Thus, to remove a malodour from a room, a considerable amount of aerosol spray would be required to be delivered throughout the room space.
We have now developed an improved method of counteracting or neutralising an airborne malodour.
Accordingly, the present invention provides a method of counteracting or neutralising airborne malodour comprising directing at the source of the malodour liquid droplets from a spray device containing a malodour counteracting composition the method comprising imparting a unipolar charge to the said liquid droplets by double layer charging during the spraying of the liquid droplets by the spray device, the unipolar charge being at a level such that the said droplets have a charge to mass ratio of at least +/xe2x88x921xc3x9710xe2x88x924 C/kg.